Russia Threatens to Target U.S. Warplanes Over Syria

“All flying objects, including planes and drones of the international coalition, detected west of the Euphrates, will be followed by Russian air defense systems as targets,” the Russian Defense Ministry said in a statement.

Weeks after President Vladimir V. Putin ordered Russian military forces to Syria in September 2015 to prop up the regime of President Bashar al-Assad, Russia and the United States signed a memorandum on preventing air incidents between the two countries.

Since then, the agreement has been a crucial link that has allowed Moscow and Washington to coordinate their military actions in the region, in which Iran, Israel, Russia, Syria, Turkey, and the United States with its allies carry out attacks in pursuit of often competing aims.

However, the agreement has also appeared to provide leverage for Moscow each time the…